1. Field of the Invention
The present invention relates to an electronic document management apparatus, an electronic document management method, and a computer program. In particular, the present invention is suited for use in management for electronic documents.
2. Description of the Related Art
Various documents (e.g., financial and tax documents) are required by law to be stored as paper media. However, with the recent advances of information technology (IT), a law that essentially allowing electronic storage of finance and tax documents and vouchers that used to be required by law to be stored as paper media went into effect. One example of such a law is the so-called e-Document Law (Japan).
Due to the effect of such a law, documents converted into electronic form by scanners (hereinafter, referred to as electronic documents) can be treated as legal evidence. To ensure authenticity of electronic documents, it is desirable to disable or at least detect tampering with electronic documents.
Japanese Patent Laid-Open No. 11-338780 discloses a technique for certification and safe storage of electronic documents for subsequent verification and retrieval. In this technique, a document certificate is generated that includes a document fingerprint generated by applying a hash function to an electronic document and a time stamp indicating the time of certification of the document. A digital signature corresponding to the document certification is generated, and the generated digital signature and document certification are transmitted to a user and managed in the same database as that for the electronic document. The use of such a document certification and a digital signature enables a user to verify the authenticity of copies of an original electronic document.
Unfortunately, for this known technique, the association of an electronic document with a document certification can be broken. If the association is broken, it is very difficult to verify that the electronic document has not been tampered with.
Therefore, the conventional techniques described above suffer from a number of disadvantages in verifying for the long term that an electronic document has not been tampered with.